Inches of rain, snow and sleet are pummeling parts of the east coast Wednesday as a massive storm system continues its crawl across the country just in time to wreak havoc on Thanksgiving travel.

With more snow and ice still to come, Winter Storm Boreas is projected to have affected about 58 million Americans by Thanksgiving morning, the Weather Channel reports. More than 200 flights were delayed on Tuesday, the Los Angeles Times reports, and more than 5,000 saw delays, in what could cause a cascade of travel woes throughout the long holiday weekend. Airports in Chicago, Denver, Cleveland and Charlotte saw some of the worst problems.

The National Weather Service has issued winter storm warnings and advisories for “the Tennessee and Ohio Valleys eastward across the Appalachians to the interior mid-Atlantic region, the lower Great Lakes as well as interior New England.” Still, the biggest problem for millions of travelers this week could be the gusty winds forecast to mix in with that wintery precipitation.

Already there have been flight cancellations, road closures, hundreds of car accidents and at least 10 deaths from crashes.

Sustained winds in New York City, for example, are forecast to hover around 20 miles per hour on Wednesday, with potential gusts of up to 55 miles per hour, according to CNN. Those winds will be only slightly calmer on Thursday – Thanksgiving Day. There’s even a chance high winds will ground some of the city’s famous Thanksgiving Day Parade balloons.

Similar windy conditions are expected throughout the northeast in combination with wintery weather, potentially creating a travel nightmare. Gusty winds can cause long delays at airports, sending reverberations through the entire country’s air traffic control system. Freezing rain is a safety hazard for aircraft as well — ice buildup can reduce the amount of lift generated by an airplane’s wings — so expect delays as airport crews work to de-ice aircraft before takeoff.

Drivers, too, will be slowed by the combinations of wind and rain or wind and snow. Visibility will be reduced and roads will be slippery, leading to slower and more dangerous than normal commutes. Those on the roads this week are advised to take caution to avoid accidents, as this storm’s already caused hundreds of collisions across the country.